316 THE OSTEOLOGY OF ELOTHERIUM. 
concaye antero-posteriorly and conyex transversely. In one species of Hlotheriwm, not 
yet identified, a somewhat different proportion of these cuneiform facets is found ; the 
mesocuneiform facet is larger and that for the entocuneiform smaller and in shape and in 
position more as in the recent pigs. 
Kowaleysky’s figures (76, Taf. XX VII, Figs. 34, 37) do not display any character- 
istic differences in the structure of the navicular between the American and the European 
species of Hlotherium. In Anthracotherium (Kowaleysky, ’73, Taf. XI, Figs. 48, 59) the 
nayvicular has a long, massive and rugose hook, given off from the plantar side; the facet 
for the ectocuneiform is relatively smaller and that for the mesocuneiform much larger 
than in Llotherium, and the two surfaces are distinctly separated. Much the same 
description will apply to Sus. In Hippopotamus the nayicular is very low and broad, and 
its distal facets are well distinguished. 
The entocuneiform is in shape not unlike the rudimentary, nodular metapodials ; it is 
high, narrow and compressed, thickest proximally and tapering distally to a blunt point. 
The navicular facet is relatively large, and is saddle-shaped, with curves the converse of 
those which occur on the corresponding surface of the nayicular. Distally, there is a 
facet on the fibular side for the plantar projection from the head of the third metatarsal. 
This element has not yet been found in connection with Anthracotherium, or with 
the European species of Elotherium. In Sus it is of quite a different form and decidedly 
smaller, while in Hippopotamus it is broader, heayier and shorter than in the fossil form. 
The mesocuneiform is firmly ankylosed with the ectocuneiform, but its shape is, 
nevertheless, clearly distinguishable ; it does not extend quite so far distally as the latter and 
is very small, especially transversely, and narrows toward the distal end. Its facet for the 
second metatarsal is obscurely displayed and it has no contact with the third. In /. magnum 
(Kowaleysky, Taf. XX VII, Figs. 35, 37) the two cuneiforms are even more completely 
fused than in the American species. In Anthracotherium the mesocuneiform is separate 
and has a large surface for articulation with the second metatarsal, as is also the case in 
Hippopotamus. In Sus this element is likewise distinct, but higher and narrower, and 
articulates with the second metatarsal more extensively than with the third. 
The ectocuneiform is a large bone, of irregularly quadrate shape; its proximal 
surface bears a large, plane facet for the navicular, and the distal end is occupied by a 
still larger surface for the third metatarsal ; the latter is abruptly contracted toward the 
plantar side. On the tibial side and distal to the mesocuneiform is a minute lateral facet 
for the second metatarsal. The contact with the cuboid is restricted to two facets near 
the proximal end, one dorsal and the other plantar, of which the latter is the smaller, but 
the more prominent. In Z. magnum this bone is yery much as in the American species, 
but the distal facet is of a different shape, not contracting so much toward the plantar 
